HHV-6 and the Brain
Novel Herpesvirus Protein is Associated with Altered Nervous System Cell Activity and Chronic Fatigue Syndrome and Depression
"A study suggests that a "smoldering" central nervous system (CNS) infection may play a role in conditions that plague millions of Americans. Kazuhiro Kondo, MD, PhD, of the Jikei University Medical School in Tokyo identified a novel human herpesvirus-6 (HHV-6) protein present in Chronic Fatigue Syndrome (CFS) patients but not healthy controls that may contribute to psychological symptoms often associated with that and other disorders."
"Kondo identified a novel HHV-6 protein associated with latent (non-replicating) HHV-6-infected nervous system and immune cells. Transfecting this new protein, called SITH-1 (Small Intermediate Stage Transcript of HHV-6), into nervous system cells called glial cells, resulted in greatly increased intracellular calcium levels. Increased intracellular calcium levels are believed to play an important role in psychological disorders and can contribute to cell death. Expressing the SITH protein though the use of an adenoviral vector in mouse resulted in manic-like behavior."
"A serological study indicated that 71% of CFS patients with psychological symptoms and none of the health controls possessed the antibody against the SITH-1 protein (p < .0001). Further tests indicated that 53% of depression and 76% of bipolar depression patients possessed the antibody."
http://www.medicalnewstoday.com/articles/112548.php
"HHV-6 is probably the most neurotropic virus known. Neuroinvasion has been documented in infants with primary infection, in focal encephalitis, in children and adults with AIDS, in recipients of bone marrow transplants, as well as in immunologically competent children and adults. Challoner et al. (78) reported viral DNA sequences in approximately two thirds of brain specimens and viral antigen expression in a number of cell types (e.g., astrocytes, macrophages, epithelial cells, endothelial cells of blood vessels) at very similar frequencies in specimens from healthy persons and multiple sclerosis patients. Astrocytes were confirmed as a susceptible cell population, although in a subsequent study only samples from AIDS patients were positive (79)" http://www.cdc.gov/Ncidod/eid/vol5no3/campadelli.htm
Infection with an Endemic Human Herpesvirus Disrupts Critical Glial Precursor Cell Properties
The Journal of Neuroscience, May 19, 2004, 24(20):4875-4883;
Cortical liquefaction in severe human herpesvirus 6 encephalopathy
{Takanashi et al. Neurology.2006; 66: 452-453}(http://www.neurology.org/cgi/content/long/66/3/452)